Compressor and controlling means therefor



June 28, 1960 A. BLACKMAN 2,942,774

COMPRESSOR AND CONTROLLING MEANS THEREFOR Filed March 2, 1956 7Sheets-Sheet 1 INVENTOR flzezander fiZac/Itman ATTORNEYS June 28, 1960A. BLACKMAN 2,942,774

COMPRESSOR AND CONTROLLING MEANS THEREFOR Filed March 2, 1956 7Sheets-Sheet 2 INVENTOR AZez a nderEZac/Zman June 28, 1960 A. BLACKMAN2,942,774

COMPRESSOR AND CONTROLLING MEANS THEREFOR Filed March 2, 1956 7Sheets-Sheet 3 .A z'zander' BZacZmun ATTORNEYS June 28, 1960 A. BLACKMAN2,942,774

COMPRESSOR AND CONTROLLING MEANS THEREFOR Filed March 2, 1956 7Sheets-Sheet 4 INVENTOR Alexa naler BZacZman ATTORN Y5 June 2 1 A.BLACKMAN 2,942,774

COMPRESSOR AND CONTROLLING MEANS THEREFOR Filed March 2, 1956 7Sheets-Sheet 5 TEL INVENTOR AZezan der BZac/Fman June 28, 1960 A.BLACKMAN 2,942,774

COMPRESSOR AND CONTROLLING MEANS THEREFOR Filed March 2, 1956 7Sheets-Sheet 6 INVENTOR Alexander fiZac/Zma 71 J1me 1950 A. BLACKMAN2,942,774

COMPRESSOR AND CONTROLLING MEANS THEREFOR Filed March 2, 1956 7Sheets-Sheet 7 H732 Jag 0 754 f 114- .715 INVENTOR JJJQ 77J Az dfizaczman 67 J15 1J3 1P U 11 7 TTO EYS United States Patent coMrREssonAND CONTRGLLING MEANS nnznnron Alexander Blackmail, New Orleans, La.,assignor of three-fifths to McDonald L. Stephens, New Orleans,

Filed Mar. 2, 1956, Ser. No. 569,116

'3 Claims. (Cl. 230-138) This invention relates generally toretrigeration or air conditioning apparatus in which the expansion of acompressed gas is utilized to produce temperature reduction.Specifically, it relates to a novel rotary gas compressor and to novelmeans for varying the compressor output as required.

The compressor is somewhat similar to prior compressors in that astator, an eccentric rotor and rotor-driven piston blades coact informing gas receiving and compressing chambers. In prior compressorswith which I am familiar, the piston blades are slidable in and disposedradially of the rotor. Thus, each blade occupies a position radial tothe stator, only when it reaches a plane common to both the rotor axisand the stator axis. At each side of this plane, the angular relation ofthe blades with respect to the stator wall constantly changes duringrotor rotation. Therefore, sharp corners connot be maintained on theouter ends of the blades and said outer ends must either be initiallyrounded or will become rounded by wear. As these rounded endsnecessarily have only line contact with the. stator wall, it ispractically impossible to provide a gas-tight seal between blades andstator wall.

The present'invention aims to overcome the'above difficulty by providinga novel well sealed construction in which the piston blades remaininvariably in strict radial relation with the stator and in whichnecessary sliding and rocking movements of said blades with respect .tothe eccentrically positioned rotor are permitted by novel rocker meansrockably mounted on said rotor and slidably contacting with said blades.This construction also causes succeeding blades to swing away from eachother during half of each rotor revolution and to swing toward eachother during the remainder of each rotor revolution. These movementsresult in circumferential expansion and contraction of the gas receivingand compressing chambers in addition to the radial expansion andcontraction caused by the relative eccentricity of the rotor and stator.

Another object of the invention is to provide an improved constructionin which provision is made for relatively shifting the stator and rotorto change the relative eccentricity thereof and thereby vary the sizesof the gas receiving and compression chambers to vary the compressoroutput.

Yet another object is to provide an improved construction in whichprovision is made for relatively shifting the stator and rotor fromoperative eccentric relation with each other, into coaxial relation witheach other to terminate compressor output when required.

A further object is to provide a novel construction in which the statoris shiftable with respect to the rotor to vary and terminate compressoroutput as required.

A still further object is to provide an improved construction in whichthe stator and rotor are yieldably biased toward maximum eccentricrelation with each other, and in which an expansible hydraulic chamberis utilized to relatively shift said stator and rotor toward or to axialalignment as required.

2,942,774 Patented June 28, 1960 Yet another object is to provide anovel construction in which the stator is shiftable with respect to therotor, and in which said stator forms one wall of the aforesaidexpansible chamber.

A further object is to provide a novel construction in which a pump isdriven by the compressor and utilized to supply a hydraulic fluid to theaforesaid expansible chamber to effect relative shifting of the statorand rotor.

A still further object is to provide a novel construction in which theingoing gas is utilized for compressor cooling.

Yet another object is to provide a novel control unit for automaticallyeffecting relative shifting of the rotor and stator as required, tovarycompressor output or terminate said output, in accordance with theneeds of the system in which the compressor is used.

Further objects are to form each blade engaging rocker of two steppedand slidably overlapped sections which are acted upon by spring means tohold their ends in fluid tight contact with the stator end walls; toprovide each piston blade with a pair. of slidably overlapped L-shapedsealing members which are held by spring means in fluid tight contactwith the statorside wall and end walls; to provide the ends of the rotorwith arcuate sealing members contacting fluid tightly with the statorend walls and also fluid tightly abutting the rockers: and to make novelprovision whereby, when a gas having lubricating qualities is beingcompressed some of this gas may be utilized to lubricate the abovementioned L-shaped sealing members.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawings.

In the drawings:

Figure 1 of the accompanying drawings is a side elevation showing thepreferred compressor, the hydraulic pump, a hydraulic fluid tank and thecontrol unit operatively connected.

Figure 2 is a vertical sectional view of the compressor substantially onthe dot and dash line 22 of Figure 3, the stator being shown in itsuppermost position for maximum output.

Figure 3 is a vertical sectional view substantially on line 3-3 ofFigure 2, the stator being again shown in its uppermost position.

Figure 4 is a fragmentary view similar to a portion of Figure 2 butshowing the stator in its fully lowered position for output termination.

Figure 5 is a diametrical sectional view of the rotor on line 5-5 ofFigure 6.

Figure 6 is an axial sectional view of the rotor on line 6-6 of Figure5.

Figure 7 is a longitudinal sectional view of one of the piston bladesshowing the preferred sealing means therein.

Figure 8 is a perspective view of one of the piston blades.

Figure 9 is a perspective view of the sealing means shown in Figure 7.

Figures 10 and 11 are perspective views showing two forms of the rockerswhich connect the piston blades with the rotor.

Figure 12 is a side elevation of the control unit.

Figure 13 is a vertical sectional view of the control unit,substantially on line 13-13 of Figure 12.

Figure 14 is a fragmentary sectional view substantially on line 1414 ofFigure 13.

Figure 15 is a fragmentary sectional view similar to a portion of Figure13 but showing different positions of parts.

V The end wall; 32 of 'the'stator S rigidly carries a 7 j I f Preferredconstruction has been disclosed in the drawings and will'b e'ratherspecifically described but atten- 7 tion is invited to the possibilityof making variations 7, within the scope of the invention,

' ,In Figure 1, the compressor (3, its pump P, the hydraulic'fluidreservoir or tank; T, and the control unit U are shown op'erativelyconnected by various gas and hydraulic fluid'lines. I These lines willbelater explained 7 after description of the compressor C, pump P, andcon- V 1101 unit U. The compressor construction'willfirst be describedand attention is directed to Figures 2 to 6 V i V I Compressor C Ahousing H is provided having supporting legs 1 whereby it maybestationarily mounted. This housing includes a continuous side wall 2having opposed, par:

allel, vertical, internal surfaces 3 (Figures 2' and -4),' aridstopshoulders 4 and 5 at the upper and lower vends of said surfaces,respectively. A"vertical and wall 6 (Figure 3) is'secured 'by screws 7to one edge of the side wall 2. This end wall 6 is formed with aninternal recess, constituting a'receiving chamber 8 'for the gas to V becompressed, and a gas inlet '9 is provided for said chamber 8. A secondvertical, end wall 10 is secured 7 against the other edge of the sidewall 2 and is provided with a ball'bearing 11, A cap plate '12 issecured against the outer side of the end wall 10Iand is provided with ta bearing 13}.aligned with the bearing 11. 'The space at the interior ofthe cap plate 12'provides a-gas-conducting chamber 14, and a gas portl5f'extends from this chamber 14 to the top of the housing H for'comducting gas into the upper end portion of thishousin'g.

i Thecap plate '12 and end wall 10 are secured tothe t sidewall 2 bymeans'of screws 16,

1A recessed portion 17 of the cap plate 12(Eigurs 3) coacts with-a coverplate 18 informing a'housing for ing stub 36 (Figures 2j3 and 4), saidstub being coaxial with the stator side wall 25. The piston blades 37,(Figures 2, 3 and 4) have bearings '38 on their inner ends, thosebearings 38 being rotatably mounted on the stub 36 and thus maintainedin strictly radial relation with the stator side wall 25. A bushing 39'is preferably interposed between the stub 36 and the bearings 38. The

blades "37 extend outwardly to'the stator side wall 25 and are of awidth for contact with the stator end wall 32 and the end ring 33, andsaid blades are equipped with suitable sealing means 40 contacting withsaid Side wall '25, end wall32 and end ring 33. As the blades 37 remainstrictly radial to the stator S, the outer ends of these 7 blades neednot have rounded corners and will therefore have extensive contact withthe stator side wall 25 and better compression sealing will result;

A hollow rotor R (Figures 2, 3, 4, 5 and 6) coacts with the stator S andthe piston blades 37 in forming expansible gas receivingand'compres'sion chambers 41 (Figures 2 and .4), said'rotor beingcarried by a motor driven shaft 42 which is rotatably mounted in thebearings il'and 13 of, the housing H. This shaft is provided with thepump-driving worm22 aboveflmentioned. The rotor R is fluid tightlyconnected with the pistontblades37 by rocker means 43 rockablyfmountedon ,said rotor and slidably'contactingwith said blades. 7 Thus, the,rotor R will drive the blades 37 and permitfnecessary relative rockingandlsliding.

Whenthe axis of the stator S is above the axis of the rotor R (seeFigure 2 for example), the chambers 4-1 gradually expand during half of'each rotor revolution,

' for gas reception, and gradually contract during the remainder ofeachrevolution, for gas compression. When the 'stato S is downwardlyshiftedtopla'ce said stator in coaxial relation with thetrotor Rl(seeFigure-4), the

' chambers 41 remain of uniform-size during rotor rotation A stator S ismounted for vertical sliding in the housing V 23 over said stator and ahyd raulic fiuid'chamber 24 under said stator. This stator has acontinuous sidewall as which-is cylindrical internally Externally,thisside wall'25'has fiat vertical surfaces 26' (Figures 2 and 4)' sidewallZ. At the upper andlowerends of the surfaces 26, the stator sidewallZS is provided with stop shoulders '27 and 28, respectively. Theupper shoulders -2 7 coact 'with the shoulders 4 for the housing sidewall'2 to limit the upward movementof the stator '5 (see Figure 2)Similarly, the lower shoulders 28 coactwith the shoulders movement ofthe statoriS (see Figure 4). j I

.5 of the housing side wall 2 in limiting the down ivard 7H andsegregates the upper and lower end portions of 1: ;said-housing frorneach other toprovide a gas chamber and no gas compression will'occur;The gas to be. compressed enters' the chambers 41- and thec'ompressedgas discharges from the chambers in ways'which can best be explainedafter describin'g' the rotor'constructionj -For this purpose, reference.is againrmade to Figures 2 to 6.

f The rotor R has arcuate side wall sections '44 between the blades 37;"substantially segmental endfflanges 45 v: are integrally'ijoined attheir' outer edges to'one edge 'of which contact slidably with thesurfaces 3 o f; the housing V Compression springs 2? aremounted-inbosses3fi on i the upper endof the housing H to bias thestator S downwardly, andhydraulic fluid supplied to the lower chamber 24is utilized to upwardly shift said stator. 'The lower ends of thesprings 29 abut the shoulders 27 ofz the l stator wall 25, and suitablespring-adjusting screws '31 abut the upper ends of said springs 29. r

- The stator Sis provided with housing end wall 6. An end ring 33 issecured-by screws 34th the other edge of 4) are associated these eonae;3; iri' fl b h ating??? aid s e i 7 e a er at. an a V 32 (Figure 3)which is prefer bly integral with one edge of theistator sidewall '25andcontacts slidably with th e the side wall sections 44, respectively,theinner edges of "said end flanges 45 being integrally joined to a hub.46

which is integral with or otherwise secured to the shaft -;42.Additional substantially segmental'end flanges -47 "are formedintegrally with the other edges of the wallsec- 'tions 44. Theseendflanges 47 contact slidably with the v stator end wall 32,tthe end-'flanges 45 similarly contact with the stator tend ring 33 as; seen inFigure 3, and suitablearcuate seals 48 are pr ovidedr'Transverselyarcuate bearing members 49 extend from end to the end ofthe rotor Rand are integral with the end flanges 453ml 47 and with theside wall sections 44; The bearing members 49 are disposed in pairs andthe members of each pair are curved about a common line.

These bearing members rockably receive the rocker means 43' for theblades37. I r 1 f The construction above described provides aih'ollowformation for the rotor R and provision is'made whereby the gas to becompressed'is directed through this hollow rot'or'for compressorcooling; To this end, the rotor end flanges 47 have ports 50communicable with an *annular' recess 51 in the stator end wall332,and'this endwall has ports 52 extending to said recess 51 from the gasreceiving 7 chamber 8 of the housing end wall 6. Thus, the gas 7 thestator side wa'll25 and Eon? f tacts slidably with the housing end wall10. Suitable seals 35 (Figures alid tacting' end walls 5, 32

entering the compressor through the inlet 9v is directed into;the hollowrotor R; Th e rotor end flanges 45 and the stator end ring' 33 haveccimmunicableiports SS, 54 and th P s 01 i ts'a re e 5 n hs a si e fhousing end wall 10. Ports 56 extend from this recess 55 to the gaschamber. 14 at the interior cap s t ne as i th ch mber 14 flaw from thelatter through the port 15, above described, into the chamber 23 overthe stator S. One gas admission port 56 extends directly from thischamber 23 into the stator S. Another gas admission port 57 is providedin advance of the port 56, and said port 57 communicates with thechamber 23 by way of ports 58 in the stator side wall 25. The gasflowing through the ports 58 aids in compressor cooling and the twoports 57, 56 adequately supply gas to the chambers 41 during expansionof the latter.

A discharge port 60 (Figure 2) is provided for the gas compressed in thechambers 41. A check valve 61 is mounted in the stator S and controlscommunication of the discharge port 61 with a gas discharge pipe 62which is integral with or otherwise secured to the stator side wall 25.The pipe 62 extends slidably through suitable sealing means 63 to theexterior of the housing H and is to be hose-connected to the usualcondensor of the refrigeration or other system in which the compressoris used.

The expansion and contraction of the chambers 41 is the result of twocontributing factors, first the eccentric relation of the rotor R andstator S, and second relative swinging movements of the piston blades37. Due to the construction employed, succeeding blades swing away fromeach other during half of each rotor revolution (during the intakecycle), and said blades swing toward each other during the remainder ofeach rotor revolution (during the gas compression cycle). This expansionand contraction of the chambers 41 in two directions, results in highefliciency of the compressor.

When the compressor is to be operated at maximum output, the stator isfully raised as shown in Figure 2, to dispose said stator at maximumeccentricity to the rotor R. As this eccentricity is decreased byraising the stator S, the output is correspondingly decreased and whenstator and compressor are coaxial (Figure 4) there is no output. It willbe recalled that the springs 29 bias the stator S downwardly and thathydraulic fluid pressure is utilized in the chamber 24 to raise saidstator. A port 64 is shown in Figure 2 for admitting the hydraulicpressure to the chamber and for relieving pressure from this chamber asrequired.

In addition to the general structure above described, the compressorpreferably includes numerous details. Assuming that Freon or other gashaving lubricating qualities, is to be handled bythe compressor, some ofthis gas may be conducted to the contacting surfaces of the stub bushing39 and blade bearings 38 through suitable ports including a supply port65 (Figure 3) in the stub 36 and communicating with the chamber 8. Ports66 and 67 may also be provided for conducting some of the gas to thebearings 11 and 13, respectively. Another port 68 is shown in the rotorshaft 42 for conducting some of the gas to a chamber 69 in which sealingmeans 70 for said shaft is located. Another port 71 is shown directlyplacing the chambers 14 and 69 in direct communication with each other.

In Figure 7, one of the piston blades 37 is shown as having chambers 72,gas ports 73 leading to said chambers 72, and gas ports 74 extendingfrom said chambers into the recess 75 which receives the sealing means40. This sealing means (see Figures 7 and 9) preferably comprises twostepped and overlapped sealing members 76, and a spring 77 for holdingthem against the end members of the stator S. Also, a spring 78 (Figure7) is shown to hold the sealing members 76 against the stator side wall25.

In Figure 10, a rocker is shown consisting of two stepped interengagingsections 79 and springs 80 for exerting outward longitudinal pressurethereon. Each rocker section 79 has a flat inner side 81 for slidablecontact with one of the piston blades 37, and a transversely arcuateouter side 82 for contact with one of the bearing members 49 of therotor R. One of these rockers is disposed at one side of each blade 37and one at the other side thereof, and the arcuate outer sides 82 thencurve about a common center. These arcuate sides 82 gas-tightly contactwith the bearing members 49 of the rotor, andthe outer ends of thesealing members 79 gas-tightly contact with the end members of thestator.

In Figure 11, a one-piece rocker 83 is shown which could be employedinstead of the rocker of Figure 10 but with less efliciency.

Control unit U The construction of the control unit U is shown inFigures l2, l3, l4 and 15 to which attention is now directed. A casingbody 84 is provided, said body having two parallel vertical bores 85 and86 which both open through the lower end of said body. An end plate 87is secured to the body 84 by screws 88 and spans the lower ends of thebores 85, 86. The upper end of the body 84 is provided with a shallowrecess 89 at the upper end of the bore 86 and with a gas inlet 90 intosaid recess. The other bore 85' has a closed upper end 91, an upperhydraulic fluid outlet port 92 near said upper end, and a lowerhydraulic fluid outlet port 93 between the ends of the bore. A verticalport 94 is formed in the body 84 between the bores 85 and 86, the upperend of said port 94 being in communication with the upper end of thebore 85. The lower end 95 of the port 94 opens into the bore 85 oppositethe lower hydraulic fluid outlet port 93.

A lower diaphragm 96 lies upon the upper end of the body 84 and spansthe recess 89 to coact with the latter in forming a gas-receivingchamber 97. The diaphragm 96 has a relatively large effective area. Aspacer ring 98 lies upon the peripheral portion of the diaphragm 96, andan upper diaphragm 99 lies upon said spacer ring, said upper diaphragm99 having a relatively small effective area. A lower cap 100 lies uponthe peripheral portion of the diaphragm 99, and this cap and diaphragmcoact in forming a lower hydraulic fluid chamber 101. A port 102 placesthis chamber 101 in communication with the upper end of the bore 84. Anupper cap 103 lies upon the cap 100 and coacts with the latter informing an upper hydraulic fiuid chamber 104. This chamber 104 has aninlet 105, and a central aperture 106 is provided from said chamber 104to the chamber 101. Screws 107 secure all of the elements 96, 98, 99,100 and 103 to the body 84.

A valve 108 is provided for closing and opening the aperture 106, saidvalve being downwardly closeable upon a seat 109 on the cap 100. Aspring 110 biases the valve 108 toward closed position and is providedwith an adjustmg screw 111. A stem 112 extends downwardly from the valve108 and is secured to both of the diaphragms 96 and 99.

A sleeve valve 113 is slidable in the bore 85 and has arms 114projecting downwardly through openings 115 (Figure 14) in the end plate87. Longitudinal slots 116 are formed through opposite sides of thesleeve valve 113, and the lower ends of said slots are cooperable withthe port 93 and the lower end 95 of the port 94, respectively.

A substantially horizontal lever 117 is disposed under the end plate 87,and one end of this lever is linked at 118 to the lower ends of thesleeve valve arms 114, the other end of said lever being fulcrumed tothe end plate 87 by linkage 119. A vertically elongated bellows 120 anda spring 121 therein, are employed to operate the lever 117. The bellows120 is disposed within the bore 86 and has its lower end fluid-tightlysecured at 122 to the end plate 87. The upper end wall 123 of thebellows 120 is secured to the upper end of a rod 124, the lower end ofthis rod being pivoted at to the lever 117. The spring 121 surrounds therod 124 and biases the bellows toward extended position, and bellowsextension is limited by a suitable stop 126. The lower end of the spring121 abuts an adjusting screw. 12 7 through which the, rod 124. extendsslidably. The bellows may 'ventithrough screw or a separate vent 128maybe provided This vent estends through the end plate 87 andcommunicates with a protecting housing 129 in which the lever 117 islocated. The bellows 120 is subjected to gas pressure in the chamber 97and when said pressure acts to. contract said bellows, the rod 124 andlever 117 slide the sleeve valve 113 downwardly. V

A piston valve 139 is slidable in the sleeve valve 113 and has a head131 coacting with the closed end of the bore 85 in forming a hydraulicfluid chamber 132. The

. piston valve'13 0 has aperipheral groove 133 forv cooperation with the'upperends of the slots 116 of the sleeve v lve 11 'sp' hts ie-a s, u whh t n valve 131} and reacts, against an adjusting screw 135 threadedthrough the end plate 87. Piston rings 1 35 are providedfor sealingbetween the piston valve 130 and the sleeve valve 113, and sealing rings136; are provided for sh ns b n a l f h' 4. he Wall h h hore. s

Connections between compressor Q, control unit U and tank T Thecompressor C, pump P, control unit U and hych'auliciiuid tanl: T areconnected by various lines as seen in higure -1 However, Figures 2 ,3and 13 showing portions-of the lines should' also' be kept in view.

'A hydraulic fluid line 137 extends from the lower end oi the tank T tothe inlet oi the pump P, and another h dra l fl f h 1 8 ext n s fr m,the m Child to the admission port 1&5 (Figure 13 of the hydraulicchamber104. A branch line 139 extends from the line 133 to'the tank Tand includes a reliei valve 14! for relieving excess hydraulic pressureand returning it to said tank; A line 141 is provided to .equaliae' thepressure in the top of the tank T with that in the gas 'Chamb er 14b tthe compressor C, Iriithc present disclosure, this line l ilgommunicates with thesealcontaining chamber 69 (Figure 3), whichchambercommunicates with the ohamberll 'through the port 71'.Anotherhydraulic line, id lcconnects the port 92 (Figure 13') oi thecontrol unit with-the port 6 4 (Figure 2) 5g the'hydraulic chamber ander the stator S of the compressor C, and yet another hydraulic line143 extends from the port '93 of. i said controlunitU to the tanl; T.

A gas line l l'places the gas admisisonf port 99(Fig- 7 ure l3) ofthejcontrol chamber 97 in communication with {the pressure of the gasflowing through the chamber 14- V on its way to the compressor chambers41 (Figures'Z and V '4) for compression. Also, due to the line 144, thehellows 120' is subjected to said gas pressure.

.ating the bellows 120 to thereby operate the sleeve *valve 113; 'Whenthe valve 108 is open, hydraulic fluid sup- V V 7 Thus, this gaspressure isinstrumental in operating the diaphragm ,96 to open the'valve 108 and is also instrumental in oper- 'in the chamber 132 andthereforein the compressor chamber 24 as required. Here, it'should be.recalled that the hydraulic pressureiin chamber '24 controls theposition of the statorS'with res'pectto the rotor R, and that theposition of said stator dictates the compressor output. Asthe gas leavesthelow'pressure side of the system for recompression' into the highpressure, side, the pressure ofsaid gas varies from a'minimum to amaximum of around 40 pounds, and it is estimated that the hydraulicpressure supplied by the pump Bshould double the pres; sure of the gas,from minimum to. maximumrThus'the. relative effective areas of thediaphragms 96"and 99 are such as to 'properly'utilize these gas andhydraulic pres suresto automatically actuate the control unit U andthereby automatically control compressor output in ac: cordance with theneeds of the system. j

Assuming that the compressor is pumped down, there would be noappreciable hydraulic pressure'in the cham: ber 24 and the stator Swould be in axial alignment with the rotor R (Figure 4). Thus, uponcompressor starting, the compressor chambers 41 would neither expand norcontract'and no gas compression would occur. When the switch of thecompressor driving motor is turned on, the customary solenoid valve ofthe system opens and releases the'liquid refrigerant to the usualexpansion valve. In passage through'the expansion valve, the refrigerantis transformed as usual into a gas which is received in the low pressureside of the-system. Thus, the gas pressure in the compressor C and inthe chamber 97 of the control unit U' will gradually increase; At thesame time, the pump P is building 'up'hydraulic pressure to the limit inthe chamber 194 of the control unitU; The built up hydraulic pressure inchamber 104 is trapped therein by the valve 108 andthis valve does notopen-Buntil the gas in chamber 97 reaches the pressure for which thecon; .tIbITl-lillllfU'lS set. In the meantime, the, compressorC hasbeenoperating without :output due to; the axial'alignment of rotorlR andstator S and ample time has been "allowedfor the chambers toclear of anyaccumulated oil and liquid whiic'hmight otherwise cause slugging.

As'soon as valve 108 opens,,the previously trapped hydraulic pressure isreleased from the chamber 1Q4 to the chajmberi 101, thjence through port102tocharnber 132 and thence through line 14210 the chamber24 under.thestator S. Consequently, this stator is moved upwardly to startcompressor operation; I However, due to the sleeve'valve 113 and pistonvalve 130,:the control unit U only admitssuflicient hydraulic pressuretochamber 24 .to causethe compressor outputrto meet the demands of the gaspressure in the low pressure side of the system. -As above stated, it isestimated'thatthe -hydraulicpressure should double the gas pressure."Therefore, if the 'gasflin'the low pressure side of the systemand'in'cham- 'ber 97 of the'c'ontrol unit U has a relatively lowpressure 0f say 10 pounds, only 20' pounds of hydraulic pressure will beadmitted to the chamber 24andthis is sufficient -to only partially raisethe stator S (about one-fourth of its travel) to the required positionto cause the compressor to handle the 10 pounds of gas pr essurepMoreover,

3 as the gaspressure rises or falls," the control unit U in-' pressurechamber '24 and the position .of the stator S' ;is thus changedtoproperly relate the compressor output sures a corresponding rise or fallofthe hydraulidfluid Y 17 -':plied to the chamber 104 b the pump P floth h withthe pressure'of the gas to be compressed.

Assuming that the control unit is sttdopen. the valve lilhat 10 poundsgas pressure, this amount of pressure "acts on the diaphragm to ope nsaidiialve 108; and thisvalve will remain open'untilthehydraulic-pressure increases to 20 'pounds, whereupon this hydraulicpressurewill act on the diaphragm 99-to againclose said valve. V 1

. "Relief of hydraulic pressure from chamber 24 to per- 1 mit loweringof the stator S correspondingly to any lowering of the gas pressure iseffected by the sleeve valve 1133x161 piston valve"l3tl.' 'In this.connection, it should lapertu're 106 into chamber 101', from thischamber r through port 102 into chamber 132, and from this chami1??? hroh li .4 to c ambe (F s 2 ahd V fof thecompre'ssor C. the hydraulicpressure inzc'r'eases, it acts on diaphragm 99 to cause movement of Vthe valve ills toward closed position. In view of the factfthatlthepiston valve lfatl is subjected to the hydraulic ,piessure inchamber'l32 and thebellows 121} which operfates the sleeve valve 113' issubjected to the pressure of the gas entering the .gas chamber 9.7,saidsleeve valve 'gi rh fhh t 9 vit sh ate the hrdrehh hrsh h "75 berecalled that the head 131 of the piston valve 130 is subjected to thehydraulic pressure in the chamber 132, and the bellows 120 whichoperates the sleeve valve 113 is subjected to the gas pressure inchamber 97. The above mentioned' pounds of gas pressure compresses thebellows 120 sufl'iciently to move the sleeve valve 113 downwardly aboutone fourth of its travel. Also, the above mentioned pounds of hydraulicpressure presses the piston valve 130 down about one-fourth of itstravel. In these one-fourth-down positions, the sleeve valve 113 andpiston valve 130 do not cause any relief of hydraulic pressure from thechambers 132 and 24, and the stator S thus remains in the one-fourth-upposition to which it has been moved by the 20 pounds of hydraulicpressure. However, if the gas pressure decreases to say 7 pounds, thebellows 120 expands sufiiciently to raise the sleeve valve 113 to aposition in which its slots 116 communicate with the groove 133 of thepiston valve 130. At this time, the lower end of one slot 116 is incommunication with the lower end 95 of the port 94 and the lower end ofthe other slot 116 is in communication with the lower end of the port93. Thus, hydraulic pressure is released through the line 143, thepressure in the compressor chamber 24 is correspondingly lowered, andthe stator S moves downwardly to adjust the compressor output forhandling the seven pound gas pressure.

If the gas pressure to be handled by the compressor increases to 40pounds, the control unit U will supply hydraulic pressure at 80 poundsto the chamber 24, thereby raising the stator S to the position ofFigure 2, for maximum compressor output. The sleeve valve 113 and pistonvalve 130 then occupy fully lowered positions and the slots 116 are thenout of communication with the groove 133 to trap the 80 pounds ofhydraulic pressure in said chamber 24 until the gas pressure againlowers, whereupon said valves eifect lowering of the hydraulic pressurein accordance with the gas pressure and change the position of thestator S accordingly.

From the foregoing, it will be seen that novel and advantageousprovision has been disclosed for attaining the desired ends. However,attention is again invited to the possibility of making variationswithin the scope of the invention.

I claim:

1. A rotary compressor comprising a stationary housing having a sideWall and two end walls secured to said side wall, one of said end wallshaving a gas-receiving chamber in its inner side and a gas inlet forthis chamber, the other of said end walls being provided with a shaftbearing; a cap plate secured against the outer side of said other endwall and having a second shaft bearing aligned with the aforesaid shaftbearing, the interior of said cap plate constituting a gas-conductingchamber; a stator within said housing, spaced downwardly from the upperend of said housing and segregating the upper and lower portions of saidhousing from each other, said stator being vertically shiftable in saidhousing and comprising a side wall, a complete end wall contacting withsaid one end wall of said housing, and an end ring contacting with saidother end wall of said housing; means for raising and lowering saidstator; a hollow rotor within said stator and disposed eccentricallythereof, said hollow rotor having a drive shaft extending through theaforesaid shaft bearings, said hollow rotor having end memberscontacting with said complete end wall and said end ring of said statorrespectively; piston blades disposed radially of said stator andextending from the interior to the exterior of said rotor; bearing meansmounting the inner ends of said blades on said complete end wall of saidstator, said bearing means being coaxial with the stator side wall; androcker means slidably and rockably connecting said blades with saidrotor; the aforesaid end wall and end ring of said stator, the aforesaidend members of said rotor, and the aforesaid other end wall of saidhousing having passages for conducting gas from the aforesaidgas-receiving chamber into the hollow rotor and from this hollow rotorinto the aforesaid gas-conducting chamber, a gas passage from thisgas-conducting chamber to the space between the upper end of theaforesaid housing and the stator, said stator having means for admittingthis gas to its interior for compression, said stator also having acompressed gas outlet.

2. A structure as specified in claim 1; said means for admitting gas tothe interior of the stator comprising one port extending directly fromsaid space to the stator interior, a second port spacedcircumferentially from said one port, and an arcuate port in the statorside wall and extending from said space to said second port.

3. A structure as specified in claim 1; together with spring meansacting on said stator and reacting on said housing for biasing saidstator downwardly into eccentric relation with said rotor, and means foradmitting fluid under pressure into the lower end of said housing toraise said stator into axial alignment with said rotor.

References Cited in the file of this patent UNITED STATES PATENTS800,023 Sharpneck Sept. 19, 1905 963,358 Caverno July 5, 1910 973,833Wilber Oct. 25, 1910 1,105,076 Hayden July 28, 1914 1,133,772 WhitingMar. 30, 1915 1,686,505 Stastny Oct. 2, 1928 1,980,726 Higbee Mar. 13,1934 2,031,749 Vincent Feb. 25, 1936 2,134,219 Tilton Oct. 25, 19382,291,424 Wichorek July 28, 1942 2,521,592 McManus Sept. 5, 19502,678,607 Hufferd et a1 May 18, 1954 2,716,469 Gassot Aug. 30, 19552,724,339 OConnor et a1 Nov. 22, 1955 2,725,890 Kanuch Dec. 6, 19552,740,256 OMalley Apr. 3, 1956 2,749,708 Douglas June 12, 1956 2,829,603Clark Apr. 8, 1958 FOREIGN PATENTS 184,695 Great Britain Aug. 24, 1922457,029 Italy Apr. 2, 1949

